Propeller for vessels and aircraft



Nov. 4, 1930. M. SCHUL PRQPELLER FOR VESSELS AND AIRCRAFT Filed Aug. 2, 1928 Juvezziars I M224 JCll/Z B M Attorney Patented Nov. 4, 1930 UNITED. STATES MAX serum, or BRUssELs, BELGIUM PROPELLER FOR VESSELSAND AIRCRAFT j 7 Application filed August 2, 1928, Serial No. 296,973, and m eeiaaiiy Aii utt 3, 192a I i ring or on a plurality of such rings, or on a flexible metal band oron a plurality of such bands, which encompasses, or encompass, the

hull of the vessel or the body of the aircraft wholly or partly, and is, or are, driven by the motor or engine either directly orby the in- 10 termediary of cog-wheels, friction wheels,

chain-wheels, or the like.

I am aware of the fact that it has already been proposed to build vessels in which the conically shaped end portions, i. e. the bow and the stern, are connected with one another by a middle portion surrounded with a movable shell provided with screw-threads, and that it also has been already proposed to attach propeller blades to a cylindrical hub so built into the hull of the vessel that the water flows past'it with a very slow speed. Further. more, it has already been proposed to attach normal aircraft propeller blades to a ring encircling the entire body of the machine and being supported on it; and finally, it has been proposed to connect certain parts of propeller blades by arms with a shaft, the thus constituted propeller being completely immersed.

Now, in none of these known propeller designs the idea has been realized to use on a ring encompassing the hull either completely or only partly only those portions of the blade surface as propelling surfaces, the ef ficiency of which lies between the maximum efficiency and another efliciency which is from 3 to 5% lower, the idea starting from an ideal propeller and the middle of the appertaining shaft coinciding with the centre of said ring. v

The. essence of the present invention consist-s, therefore, therein that (starting from an ideal propeller having a shaft, the middle of which coincides with the centre of the said ring) only those surface portions are used as propelling surfaces, the efliciency of which lies between the maximum efiiciency and another efficiency'which is lower by from 3 to 5%. It is known that those port-ions of'a propeller .tain'ed that efficiencycurve inwhich a distinct "5% less, asalready stated.

hull and-providedwith the best-efiiciency. sur

a medium diameter (Z and 3 denotes an elethe equal pitch H are laidout as abscissae, and

blade which lie about in the mid' dle' between uesha a and the 'eakofthe blade have I a" higher eificiency" than those other portions which lie at thehub and the; peak. If the'lproportion'betweeii the"diam; w

eter of the circle on which the propeller Iele ment is lying and thepitch of the blade (which is assumed to be constantyislaid out. as abscissa, and if the efficiency of'the'p'ro peller is laid out, as ordinate,there isf ob maximum curve exists. Theoretically, an infinitely small surface stripe'on "the'propeller would correspond to the maximum of that. efficiency curve, but with consideration of the character of that curve the invention is carried out practically in this way that also those surface portions are used,'theiefficieney of which lies between the maximum efficiency and that other eificiency whichisffrom eta! a 701 Propeller blades designed according -to this invention are illustrated diagrammatically andby way of exampleonthe accom' panying drawing, on which 'Figure' 1 .is a.

view. of an ordinary propeller blade with its shaft; Figure 2' shows the eflici'encyofa propeller element as function of the 'diameterf:

relation "Figu e 3 isa front-view of avessel' provided With a rigid ring encircling the? faces ofjan ideal propeller (indicated dot ted lines) and Figure 4 isa side-viewfof'thef front half of a vessel provided'withi'the are: pelling device shown in Fig. 3. i I

On the drawing, 1, Fig. 1, denotes an element located in the immediate proximity of the propeller shaft and having a medium diameter d 2 denotes an elementelying about in the middle portionof the blade and having ment lying at the blade peak and having the medium diameter d Y Y i j a In Fig. 2 the proportions between the medium diameter of the elements 1, 2 and 3 and the efficiencies pertaining to said elements are laid out as ordinates. It can be seen from said curvethat it has a maximum about the abscissa near Near that maximum the efficiency curve extends comparatively flat, viz. between limits lying, about from 3 to 5% below said maximum. These proportions of the propeller, viz. of the ideal pro 1 peller indicated by dotted lines in Fig. 3, are, according to this invention, selected, and they are arranged on a ring 5 supported in any suitable 'i'na-nner' on the hull'near the bow.; As thesuppor'ting means, as well as'th'e ineans" for rotating said ring, are known, Ia'bstain from showing and describing these details. ,6 denotes thepropeller blades which cor- --'respond to those surface elements of the ideal propeller, the etficiency of which lies'between the maximum sefli'c'iency and 35%"less.=- Insteadof only one ringtwoor'more such rings can be. provided in a cert'aindistance from one another} The poweristifanfsniitted from g the motor-"or. engine by means of apinion 1 (no, Qshown)',leng"ging an internaltoothing ofthe sa'idringor'rings.

Q'It is no departure from the 'invention' if the j rblades,'fi n stea:d of lbeing secured toiafrigid ring,.,are afiixed; we? pliable or flexible metal bandorf t anllar ticulatedchain." In cases, I

I ,so

like these the b'lade' s urfaces, instead of rotat ing around the propeller shaft, can move in a straight linethrough' the water, transverse- 1y with respect to the longitudinal axis of Vessel, andin'steadOfapinionor the like friction wheels, chain wheels a chain, or the like-, can-be used. In all ca'se's the essence ofithe inventionresides'injmaking use exclusiyelyjofthoseblade surface portions which 3- possess and warrant highestefiiciency. r I claim; I i I Aflp ro eller for Vessels and aircraft, co n prising,in combination, a member adapted to'be move d transversely with respect to;the longitudinal axis of the hull oft'lie Vessel or the bodyof the aircraft, and blades attached to said member and ,being; formed 1by1 p01 7 tionsof'an ideal propeller, the middle of the shaft zo f 'which' coincides with t'he centre ofv saidmember, said port-ions being those, the elficiencylofwhich hes between the maximum v efficiencyigandl another elficie'ncy 'which is 

